Surface Activity, Wetting, and Aggregation of a Perfluoropolyether Quaternary Ammonium Salt Surfactant with a Hydroxyethyl Group

Abstract

This paper reports the synthesis of a novel quaternary surfactant containing a hydroxyethyl group (PFPE-C) and the surface properties of its aqueous solution (investigated by comparisons with two structurally similar chemicals, dodecyl-(2-hydroxyethyl)-dimethylammonium chloride (DHDAC) and PFPE-A). The minimum surface tension (γCMC) and critical micelle concentration (CMC) of the PFPE-C aqueous solution were 17.35 mN/m and 0.024 mmol/L, respectively. This study confirms that surfactants containing hydroxyethyl groups efficiently reduce the surface tension of aqueous solutions, and fluorocarbon surfactants exhibit better surface activity than ordinary hydrocarbon surfactants with similar structures. The micellization, aggregation, air-water interfacial adsorption, and wettability of PFPE-C aqueous solutions have been systematically investigated. Highly concentrated PFPE-C aqueous solutions exhibit good wettability on PTFE and paraffin films. Moreover, the aggregates of PFPE-C in the aqueous solution were clearly seen as vesicles on Cryo-TEM micrographs. Primary biodegradation results indicate that 19% of PFPC-C can be degraded within one week.

Surface Activity, Wettability, and Aggregation Behavior of Ecofriendly Fluorocarbon Surfactant Based on Double Perfluorinated Branched Short Chains

“…As shown in Table , the CMC values measured by conductivity method are approximately the same as those obtained by equilibrium surface tension method (Table ), demonstrating that no premicelles are produced in the three aqueous solutions . Another noticeable phenomenon is that the CMC of all three solutions, SFDC, SFDC-L, and SFDC/HTAB mixture, increased with increasing temperature (e.g., the CMC of SFDC increased from 9.81 × 10 –3 mmol/L at 25 °C to 1.47 × 10 –2 mmol/L at 45 °C).…”

“…As shown in Table 2, the CMC values measured by conductivity method are approximately the same as those obtained by equilibrium surface tension method (Table 1), demonstrating that no premicelles are produced in the three aqueous solutions. 26 Another noticeable phenomenon is that the CMC of all three solutions, SFDC, SFDC-L, and SFDC/ HTAB mixture, increased with increasing temperature (e.g., the CMC of SFDC increased from 9.81 × 10 −3 mmol/L at 25 °C to 1.47 × 10 −2 mmol/L at 45 °C). A possible reason for this is that the increase in temperature weakens the interactions of the hydrophobic chains in the surfactant molecule 26 or reduces the mutual repulsion between hydrophilic groups of the same electrical properties, 30 thus achieving the increase in the CMC.…”

“…Another noticeable phenomenon is that the CMC of all three solutions, SFDC, SFDC-L, and SFDC/HTAB mixture, increased with increasing temperature (e.g., the CMC of SFDC increased from 9.81 × 10 –3 mmol/L at 25 °C to 1.47 × 10 –2 mmol/L at 45 °C). A possible reason for this is that the increase in temperature weakens the interactions of the hydrophobic chains in the surfactant molecule or reduces the mutual repulsion between hydrophilic groups of the same electrical properties, thus achieving the increase in the CMC. In addition, the values of Δ G m θ and Δ H m θ are both negative, indicating that the formations of micelles in aqueous solution for SFDC, SFDC-L, and complexed systems are all spontaneous exothermic processes in which dispersive forces play a major role .…”

“…This is an evidence that molecular aggregates (micelles, vesicles, etc.) in solution hinder the free migration of ions …”

Indirect prediction of graphene nanoplatelets-reinforced cementitious composites compressive strength by using machine learning approaches

“…The results showed a strong correlation (R > 0.95). Amin et al 61 utilized extreme gradient boosting (XGBoost), random forest (RF), and light gradient boosting machine (LightGBM) approaches to examine the bond Strength of fiber-reinforced polymer with concrete. The LightGBM model exhibited greater precision than the RF and XGBoost approaches.…”